Lubricants



Patented Aug. 28, 1945 wail-f UNITED PATENT o rricizl LUBRIOANTs Johan.Morgan, South Oran e, N'. 3., a'ss'ign'oi' tof' v V Cities ServiceOil'Company, Newt "York,

corporation of Pennsylvania 1 I Np Drawing. Application July 9, "19 42,

Serial No. 450.287, v I

This invention relates to lubricants which are 4 more particularlyadapted for low temperature lubrication.

Many machines, such as the aeroplane, truck and automobile, operate inatmospheres which 5 may range in temperature from 50 F. to 200 F. Alubricant which is effective for lubrication in this temperature rangeshould have a comparatively uniform viscosity throughout thistemperature range.

The primary object of the present invention is to provide a lubricantand method of lubrication which are effective in a temperature range of-50 F. to 200 F.

Another object of the invention is to provide a lubricant which isstable and non-corrosive and which is capable of withstanding highbearing Pressures.

With these and other objects in View the invention consists in thelubricant and method of lubricating hereinafter described andparticularly defined in the claims.

I have discovered that the alkyl lactates have physical characteristicswhichladapt them for lubrication in a range of from 50 F.- to 200 F. Thelactates which are more particularly adapted as lubricants are the alkyllactates which are esters of a-hydroxypropionic acid or lactic acid.

The alkyl lactates, particularly adapted for lubricants, have thefollowing physical properties:

Boiling Flash Melting point point point F. F. F. Ethyl lactate 311 129But-y! lactate 370 160 Isohutyl l \ctute 350-390 l .5

These alkyl lactates are oily liquids and have the 40 followingviscosities:

be seen that allofthese lactates have apparently uniformviscositythroughout the range of 40 F. to 200 F.

All of the alkyl lactates above mentioned have good lubricating values,that is they have better lubricating values than the regular petroleumlubricating spindle oil having a viscosity of 200 at F. If 3.2%, forexample, of ethyl lactate is added to the spindle oil, the load-carryingcapacity of the oil will be increased 20%.

By adding one of the well known extreme pressure addition agents to anyof these alkyl lactates the load-carrying capacity of the lactate willbe raised to a point where it will carry very high bearing pressures.For example with an extreme pressure 4-ball testing machine ethyllactate would seize at 450 lbs. pressure. By the addition of 1% ofPolane, the ester would not seize at 1000 lbs. pressure. It has beenfound that if 1% of Polane or tricresyl phosphite, or Santolube #261 isadded to any of the alkyl lactates the load-carrying capacity would beraised to the point where they would not seize in the 4-ball testingmachine at a pressure of 1000 lbs.

The ethyl and butyl lactates are well adapted for the manufacture ofgreases. These lactates with approximately 6% of sodium soap will form agrease that is stable and will not bleed. Preferably the lactatecontains 1% of the extreme pressure additive to make the grease anextreme.

pressure carrying grease. The soap preferably is sodium stearate,although it has been found that; sodium oleate or sodium palmitate, orany of the sodium soaps of the fatty acids are adapted for makinggreases with the ethyl and butyl lactates. Such a grease may consist ofapproximately 93% of one of these lactates, approximately 6% of sodiumstearate, and approximately 1% of an extreme pressure agent.

These lactates are neutral and non-corrosive in the metal bearings inwhich they have been employed and will elfectively adhere to thebearings through the temperature range of 40 F. to 200 F.

Most of the commonly used extreme pressure addition agents are solublein the lactates and impart load-carrying capacities to the lactates.Polane is a product sold by the Patent Chemicals Company and isunderstood to be an ester of a fatty acid or a chlorinated ester of afatty acid, such as ethyl laurate or chlormethyl stearate. Santolube#261 is manufactured by Monsanto Chemical Company and defined as ametallic derivative of an alkyiated carboxylic acid containing compoundsof tin and sulIur. The ma cresyl'phosphite referred to above isdescribed in the patent to Engelke- No. 2,260,303 granted October 28,1941, and is described as a tricresyl phosphite, or a mixture oftricresyl phosphite and tricresyl phosphate. lhe above addition agentsalso; act as oiliness and anticorrosion aae Certain subject-matterdisclosed herein is claimed in divisional application Serial N0.519,649, filed January 25, 1944.

The preferred form of the invention been thus described, 'what isclaimed as new is:

l. A lubricant consisting essentially of ethyl lactate havingapproximately 1% of an extreme pressure addition agent dissolvedtherein.

2. A lubricant comprising ethyl lactate 93%, sodium stearate 6%,tricresyl phos'phite 1%.

3. A lubricant comprising ethyl lactate 93 percent, sodium stearate 6percent, and an extreme pressure addition agent 1 percent.

4. A lubricant consisting essentially of a liquid allryl lactate havingan extreme pressure agent dissolved therein in sufficient proportion toimpart extreme pressure properties to the lubricant.

8. A lubricant consisting of approximately 6% oi? sodium stearate, theremainder of the lubricant consisting essentially of ethyl lactate.

\ JOHN D. MORGAN.

